Who cares about Domain Rules?

using NUnit.Framework;

namespace BusinessRules.Evolution_Five.Tests
{
    [TestFixture]
    public class TaxBandFixture
    {
        private TaxBand m_band;

        /// <summary>
        /// The Setup method is called before each test method is called. 
        /// So we recreate a new TaxBand object before each test.
        /// </summary>
        [SetUp]
        public void Setup()
        {
            m_band = new TaxBand(0.0, 20000.00, 0.1);
        }

        /// <summary>
        /// Validates the tax rate is correct after creating a new tax band.
        /// </summary>
        [Test]
        public void ValidateTaxRateCorrectAfterCreatingNewTaxBand()
        {
            double expectedTaxRate = 0.1;

            Assert.AreEqual(expectedTaxRate, m_band.TaxRate);
        }

        /// <summary>
        /// Validates the calculate tax portion method behaves as expected.
        /// </summary>
        [Test]
        public void ValidateCalculateTaxPortion()
        {
            Assert.AreEqual(0.0, m_band.CalculateTaxPortion(0.0));
            Assert.AreEqual(1000.0, m_band.CalculateTaxPortion(10000.0));
            Assert.AreEqual(500.0, m_band.CalculateTaxPortion(5000.0));
            Assert.AreEqual(2000.0, m_band.CalculateTaxPortion(20000.0));
            Assert.AreEqual(2000.0, m_band.CalculateTaxPortion(20001.0));
            Assert.AreEqual(1254.6, m_band.CalculateTaxPortion(12546.0), 2.0);
            Assert.AreEqual(2000.0, m_band.CalculateTaxPortion(12021541.0));
        }
    }
}